[PATCH v2 21/22] 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/Makefile                   |   3 +-
 test/tasst/__main__.py          |   1 +
 test/tasst/scenario/__init__.py |  12 ++++
 test/tasst/scenario/simple.py   | 109 ++++++++++++++++++++++++++++++++
 4 files changed, 124 insertions(+), 1 deletion(-)
 create mode 100644 test/tasst/scenario/__init__.py
 create mode 100644 test/tasst/scenario/simple.py

diff --git a/test/Makefile b/test/Makefile
index 0eeaf82e..6748d38a 100644
--- a/test/Makefile
+++ b/test/Makefile
@@ -74,7 +74,8 @@ AVOCADO_JOBS = $(EXETER_JOBS) avocado/static_checkers.json
 
 TASST_SRCS = __init__.py __main__.py address.py dhcp.py dhcpv6.py ndp.py \
 	nstool.py snh.py transfer.py \
-	selftest/__init__.py selftest/static_ifup.py selftest/veth.py
+	selftest/__init__.py selftest/static_ifup.py selftest/veth.py \
+	scenario/__init__.py scenario/simple.py
 
 EXETER_META = meta/lint.json meta/tasst.json
 META_JOBS = $(EXETER_META)
diff --git a/test/tasst/__main__.py b/test/tasst/__main__.py
index 8c4efd74..491c68c9 100644
--- a/test/tasst/__main__.py
+++ b/test/tasst/__main__.py
@@ -14,6 +14,7 @@ import exeter
 
 # We import just to get the exeter tests, which flake8 can't see
 from . import dhcp, dhcpv6, ndp, nstool, snh, transfer  # noqa: F401
+from .scenario import simple  # noqa: F401
 from .selftest import static_ifup, veth  # noqa: F401
 
 
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..d8b78568
--- /dev/null
+++ b/test/tasst/scenario/simple.py
@@ -0,0 +1,109 @@
+#! /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 .. import address, nstool, transfer
+
+
+class __SimpleNet:  # pylint: disable=R0903
+    """A simple network setup scenario
+
+    The sample network has 2 snhs (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 = address.IpiAllocator()
+    (IP4, IP6) = ipa_local.next_ipis()
+    (GW_IP4, GW_IP6) = ipa_local.next_ipis()
+
+    ipa_remote = address.IpiAllocator(address.TEST_NET_2,
+                                      address.TEST_NET6_TASST_B)
+    (REMOTE_IP4, REMOTE_IP6) = ipa_remote.next_ipis()
+
+    def __init__(self, simhost, gw):
+        self.simhost = simhost
+        self.gw = gw
+
+        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('ip', '-4', 'route', 'add', 'default',
+                        'via', f'{self.GW_IP4.ip}', capable=True)
+        self.simhost.fg('ip', '-6', 'route', 'add', 'default',
+                        'via', f'{self.gw_ip6_ll.ip}', 'dev', f'{ifname}',
+                        capable=True)
+
+
+@contextlib.contextmanager
+def simple_net():
+    with nstool.unshare_snh('simhost', '-Ucnpf', '--mount-proc') as simhost, \
+         nstool.unshare_snh('gw', '-n', parent=simhost, capable=True) as gw:
+        yield __SimpleNet(simhost, gw)
+
+
+@contextlib.contextmanager
+def simple_transfer4_setup():
+    with simple_net() as snet:
+        yield transfer.TransferTestScenario(client=snet.simhost,
+                                            server=snet.gw,
+                                            connect_ip=snet.REMOTE_IP4.ip,
+                                            connect_port=10000)
+
+
+transfer.transfer_tests(simple_transfer4_setup)
+
+
+@contextlib.contextmanager
+def simple_transfer6_setup():
+    with simple_net() as snet:
+        yield transfer.TransferTestScenario(client=snet.simhost,
+                                            server=snet.gw,
+                                            connect_ip=snet.REMOTE_IP6.ip,
+                                            connect_port=10000)
+
+
+transfer.transfer_tests(simple_transfer6_setup)
-- 
@@ -0,0 +1,109 @@
+#! /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 .. import address, nstool, transfer
+
+
+class __SimpleNet:  # pylint: disable=R0903
+    """A simple network setup scenario
+
+    The sample network has 2 snhs (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 = address.IpiAllocator()
+    (IP4, IP6) = ipa_local.next_ipis()
+    (GW_IP4, GW_IP6) = ipa_local.next_ipis()
+
+    ipa_remote = address.IpiAllocator(address.TEST_NET_2,
+                                      address.TEST_NET6_TASST_B)
+    (REMOTE_IP4, REMOTE_IP6) = ipa_remote.next_ipis()
+
+    def __init__(self, simhost, gw):
+        self.simhost = simhost
+        self.gw = gw
+
+        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('ip', '-4', 'route', 'add', 'default',
+                        'via', f'{self.GW_IP4.ip}', capable=True)
+        self.simhost.fg('ip', '-6', 'route', 'add', 'default',
+                        'via', f'{self.gw_ip6_ll.ip}', 'dev', f'{ifname}',
+                        capable=True)
+
+
+@contextlib.contextmanager
+def simple_net():
+    with nstool.unshare_snh('simhost', '-Ucnpf', '--mount-proc') as simhost, \
+         nstool.unshare_snh('gw', '-n', parent=simhost, capable=True) as gw:
+        yield __SimpleNet(simhost, gw)
+
+
+@contextlib.contextmanager
+def simple_transfer4_setup():
+    with simple_net() as snet:
+        yield transfer.TransferTestScenario(client=snet.simhost,
+                                            server=snet.gw,
+                                            connect_ip=snet.REMOTE_IP4.ip,
+                                            connect_port=10000)
+
+
+transfer.transfer_tests(simple_transfer4_setup)
+
+
+@contextlib.contextmanager
+def simple_transfer6_setup():
+    with simple_net() as snet:
+        yield transfer.TransferTestScenario(client=snet.simhost,
+                                            server=snet.gw,
+                                            connect_ip=snet.REMOTE_IP6.ip,
+                                            connect_port=10000)
+
+
+transfer.transfer_tests(simple_transfer6_setup)
-- 
2.45.2