[PATCH net-next 3/4] selftests/net: Add env for container based tests

[David Wei <dw@davidwei.uk>]

Add an env NetDrvContEnv for container based selftests. This automates
the setup of a netns, netkit pair with one inside the netns, and a BPF
program that forwards skbs from the NETIF host inside the container.

Currently only netkit is used, but other virtual netdevs e.g. veth can
be used too.

Expect netkit container datapath selftests to have a publicly routable
IP prefix to assign to netkit in a container, such that packets will
land on eth0. The BPF skb forward program will then forward such packets
from the host netns to the container netns.

Signed-off-by: David Wei <dw@davidwei.uk>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
---
 .../testing/selftests/drivers/net/README.rst  |  19 ++
 .../drivers/net/hw/lib/py/__init__.py         |   7 +-
 .../selftests/drivers/net/lib/py/__init__.py  |   7 +-
 .../selftests/drivers/net/lib/py/env.py       | 163 ++++++++++++++++++
 4 files changed, 190 insertions(+), 6 deletions(-)

diff --git a/tools/testing/selftests/drivers/net/README.rst b/tools/testing/selftests/drivers/net/README.rst
index eb838ae94844..39370a83f238 100644
--- a/tools/testing/selftests/drivers/net/README.rst
+++ b/tools/testing/selftests/drivers/net/README.rst
@@ -62,6 +62,25 @@ LOCAL_V4, LOCAL_V6, REMOTE_V4, REMOTE_V6
 
 Local and remote endpoint IP addresses.
 
+LOCAL_PREFIX_V4, LOCAL_PREFIX_V6
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Local IP prefix/subnet which can be used to allocate extra IP addresses (for
+network name spaces behind macvlan, veth, netkit devices). DUT must be
+reachable using these addresses from the endpoint.
+
+  +-------------+        +----------------------------+
+  | INIT NS     |        | TEST NS                    |
+  | +---------+ |        | +------------------------+ |
+  | | NETIF   | |  bpf   | | Netkit                 | |
+  | |         |-|--------|>| nk_guest               | |
+  | +---------+ |        | | {LOCAL_PREFIX_V6}::2:2 | |
+  | +---------+ |        | +------------------------+ |
+  | | Netkit  | |        +----------------------------+
+  | | nk_host | |
+  | +---------+ |
+  +-------------+
+
 REMOTE_TYPE
 ~~~~~~~~~~~
 
diff --git a/tools/testing/selftests/drivers/net/hw/lib/py/__init__.py b/tools/testing/selftests/drivers/net/hw/lib/py/__init__.py
index d5d247eca6b7..022008249313 100644
--- a/tools/testing/selftests/drivers/net/hw/lib/py/__init__.py
+++ b/tools/testing/selftests/drivers/net/hw/lib/py/__init__.py
@@ -3,6 +3,7 @@
 """
 Driver test environment (hardware-only tests).
 NetDrvEnv and NetDrvEpEnv are the main environment classes.
+NetDrvContEnv extends NetDrvEpEnv with netkit container support.
 Former is for local host only tests, latter creates / connects
 to a remote endpoint. See NIPA wiki for more information about
 running and writing driver tests.
@@ -29,7 +30,7 @@ try:
     from net.lib.py import ksft_eq, ksft_ge, ksft_in, ksft_is, ksft_lt, \
         ksft_ne, ksft_not_in, ksft_raises, ksft_true, ksft_gt, ksft_not_none
     from drivers.net.lib.py import GenerateTraffic, Remote, Iperf3Runner
-    from drivers.net.lib.py import NetDrvEnv, NetDrvEpEnv
+    from drivers.net.lib.py import NetDrvEnv, NetDrvEpEnv, NetDrvContEnv
 
     __all__ = ["NetNS", "NetNSEnter", "NetdevSimDev",
                "EthtoolFamily", "NetdevFamily", "NetshaperFamily",
@@ -44,8 +45,8 @@ try:
                "ksft_eq", "ksft_ge", "ksft_in", "ksft_is", "ksft_lt",
                "ksft_ne", "ksft_not_in", "ksft_raises", "ksft_true", "ksft_gt",
                "ksft_not_none", "ksft_not_none",
-               "NetDrvEnv", "NetDrvEpEnv", "GenerateTraffic", "Remote",
-               "Iperf3Runner"]
+               "NetDrvEnv", "NetDrvEpEnv", "NetDrvContEnv", "GenerateTraffic",
+               "Remote", "Iperf3Runner"]
 except ModuleNotFoundError as e:
     print("Failed importing `net` library from kernel sources")
     print(str(e))
diff --git a/tools/testing/selftests/drivers/net/lib/py/__init__.py b/tools/testing/selftests/drivers/net/lib/py/__init__.py
index a18e21069f7a..6b55068d5370 100644
--- a/tools/testing/selftests/drivers/net/lib/py/__init__.py
+++ b/tools/testing/selftests/drivers/net/lib/py/__init__.py
@@ -3,6 +3,7 @@
 """
 Driver test environment.
 NetDrvEnv and NetDrvEpEnv are the main environment classes.
+NetDrvContEnv extends NetDrvEpEnv with netkit container support.
 Former is for local host only tests, latter creates / connects
 to a remote endpoint. See NIPA wiki for more information about
 running and writing driver tests.
@@ -43,12 +44,12 @@ try:
                "ksft_ne", "ksft_not_in", "ksft_raises", "ksft_true", "ksft_gt",
                "ksft_not_none", "ksft_not_none"]
 
-    from .env import NetDrvEnv, NetDrvEpEnv
+    from .env import NetDrvEnv, NetDrvEpEnv, NetDrvContEnv
     from .load import GenerateTraffic, Iperf3Runner
     from .remote import Remote
 
-    __all__ += ["NetDrvEnv", "NetDrvEpEnv", "GenerateTraffic", "Remote",
-                "Iperf3Runner"]
+    __all__ += ["NetDrvEnv", "NetDrvEpEnv", "NetDrvContEnv", "GenerateTraffic",
+                "Remote", "Iperf3Runner"]
 except ModuleNotFoundError as e:
     print("Failed importing `net` library from kernel sources")
     print(str(e))
diff --git a/tools/testing/selftests/drivers/net/lib/py/env.py b/tools/testing/selftests/drivers/net/lib/py/env.py
index 41cc248ac848..857ae0f37516 100644
--- a/tools/testing/selftests/drivers/net/lib/py/env.py
+++ b/tools/testing/selftests/drivers/net/lib/py/env.py
@@ -1,13 +1,16 @@
 # SPDX-License-Identifier: GPL-2.0
 
+import ipaddress
 import os
 import time
+import json
 from pathlib import Path
 from lib.py import KsftSkipEx, KsftXfailEx
 from lib.py import ksft_setup, wait_file
 from lib.py import cmd, ethtool, ip, CmdExitFailure
 from lib.py import NetNS, NetdevSimDev
 from .remote import Remote
+from . import bpftool, RtnlFamily, Netlink
 
 
 class NetDrvEnvBase:
@@ -289,3 +292,163 @@ class NetDrvEpEnv(NetDrvEnvBase):
                 data.get('stats-block-usecs', 0) / 1000 / 1000
 
         time.sleep(self._stats_settle_time)
+
+
+class NetDrvContEnv(NetDrvEpEnv):
+    """
+    Class for an environment with a netkit pair setup for forwarding traffic
+    between the physical interface and a network namespace.
+    +-------------+        +----------------------------+
+    | INIT NS     |        | TEST NS                    |
+    | +---------+ |        | +------------------------+ |
+    | | NETIF   | |  bpf   | | Netkit                 | |
+    | |         |-|--------|>| nk_guest               | |
+    | +---------+ |        | | {LOCAL_PREFIX_V6}::2:2 | |
+    | +---------+ |        | +------------------------+ |
+    | | Netkit  | |        +----------------------------+
+    | | nk_host | |
+    | +---------+ |
+    +-------------+
+    """
+
+    def __init__(self, src_path, rxqueues=1, **kwargs):
+        super().__init__(src_path, **kwargs)
+
+        self.netns = None
+        self._nk_host_ifname = None
+        self._nk_guest_ifname = None
+        self._tc_clsact_added = False
+        self._tc_attached = False
+        self._bpf_prog_pref = None
+        self._bpf_prog_id = None
+        self._init_ns_attached = False
+
+        self.require_ipver("6")
+        local_prefix = self.env.get("LOCAL_PREFIX_V6")
+        if not local_prefix:
+            raise KsftSkipEx("LOCAL_PREFIX_V6 required")
+
+        local_prefix = local_prefix.rstrip("/64").rstrip("::").rstrip(":")
+        self.ipv6_prefix = f"{local_prefix}::"
+        self.nk_host_ipv6 = f"{local_prefix}::2:1"
+        self.nk_guest_ipv6 = f"{local_prefix}::2:2"
+
+        rtnl = RtnlFamily()
+        rtnl.newlink(
+            {
+                "linkinfo": {
+                    "kind": "netkit",
+                    "data": {
+                        "mode": "l2",
+                        "policy": "forward",
+                        "peer-policy": "forward",
+                    },
+                },
+                "num-rx-queues": rxqueues,
+            },
+            flags=[Netlink.NLM_F_CREATE, Netlink.NLM_F_EXCL],
+        )
+
+        all_links = ip("-d link show", json=True)
+        netkit_links = [link for link in all_links
+                        if link.get('linkinfo', {}).get('info_kind') == 'netkit'
+                        and 'UP' not in link.get('flags', [])]
+
+        if len(netkit_links) != 2:
+            raise KsftSkipEx("Failed to create netkit pair")
+
+        netkit_links.sort(key=lambda x: x['ifindex'])
+        self._nk_host_ifname = netkit_links[1]['ifname']
+        self._nk_guest_ifname = netkit_links[0]['ifname']
+        self.nk_host_ifindex = netkit_links[1]['ifindex']
+        self.nk_guest_ifindex = netkit_links[0]['ifindex']
+
+        self._setup_ns()
+        self._attach_bpf()
+
+    def __del__(self):
+        if self._tc_attached:
+            cmd(f"tc filter del dev {self.ifname} ingress pref {self._bpf_prog_pref}")
+            self._tc_attached = False
+
+        if self._tc_clsact_added:
+            cmd(f"tc qdisc del dev {self.ifname} clsact")
+            self._tc_clsact_added = False
+
+        if self._nk_host_ifname:
+            cmd(f"ip link del dev {self._nk_host_ifname}")
+            self._nk_host_ifname = None
+            self._nk_guest_ifname = None
+
+        if self._init_ns_attached:
+            cmd("ip netns del init", fail=False)
+            self._init_ns_attached = False
+
+        if self.netns:
+            del self.netns
+            self.netns = None
+
+        super().__del__()
+
+    def _setup_ns(self):
+        self.netns = NetNS()
+        cmd("ip netns attach init 1")
+        self._init_ns_attached = True
+        ip("netns set init 0", ns=self.netns)
+        ip(f"link set dev {self._nk_guest_ifname} netns {self.netns.name}")
+        ip(f"link set dev {self._nk_host_ifname} up")
+        ip(f"-6 addr add fe80::1/64 dev {self._nk_host_ifname} nodad")
+        ip(f"-6 route add {self.nk_guest_ipv6}/128 via fe80::2 dev {self._nk_host_ifname}")
+
+        ip("link set lo up", ns=self.netns)
+        ip(f"link set dev {self._nk_guest_ifname} up", ns=self.netns)
+        ip(f"-6 addr add fe80::2/64 dev {self._nk_guest_ifname}", ns=self.netns)
+        ip(f"-6 addr add {self.nk_guest_ipv6}/64 dev {self._nk_guest_ifname} nodad", ns=self.netns)
+        ip(f"-6 route add default via fe80::1 dev {self._nk_guest_ifname}", ns=self.netns)
+
+    def _tc_ensure_clsact(self):
+        qdisc = json.loads(cmd(f"tc -j qdisc show dev {self.ifname}").stdout)
+        for q in qdisc:
+            if q['kind'] == 'clsact':
+                return
+        cmd(f"tc qdisc add dev {self.ifname} clsact")
+        self._tc_clsact_added = True
+
+    def _get_bpf_prog_ids(self):
+        filter = json.loads(cmd(f"tc -j filter show dev {self.ifname} ingress").stdout)
+        for bpf in filter:
+            if 'options' not in bpf:
+                continue
+            if bpf['options']['bpf_name'].startswith('nk_forward.bpf'):
+                return (bpf['pref'], bpf['options']['prog']['id'])
+        if self._bpf_prog_pref is None:
+            raise Exception("Failed to get BPF prog ID")
+
+    def _attach_bpf(self):
+        bpf_obj = self.test_dir / "nk_forward.bpf.o"
+        if not bpf_obj.exists():
+            raise KsftSkipEx("BPF prog not found")
+
+        self._tc_ensure_clsact()
+        cmd(f"tc filter add dev {self.ifname} ingress bpf obj {bpf_obj} sec tc/ingress direct-action")
+        self._tc_attached = True
+
+        (self._bpf_prog_pref, self._bpf_prog_id) = self._get_bpf_prog_ids()
+        prog_info = bpftool(f"prog show id {self._bpf_prog_id}", json=True)
+        map_ids = prog_info.get("map_ids", [])
+
+        bss_map_id = None
+        for map_id in map_ids:
+            map_info = bpftool(f"map show id {map_id}", json=True)
+            if map_info.get("name").endswith("bss"):
+                bss_map_id = map_id
+
+        if bss_map_id is None:
+            raise Exception("Failed to find .bss map")
+
+        ipv6_addr = ipaddress.IPv6Address(self.ipv6_prefix)
+        ipv6_bytes = ipv6_addr.packed
+        ifindex_bytes = self.nk_host_ifindex.to_bytes(4, byteorder='little')
+        value = ipv6_bytes + ifindex_bytes
+        value_hex = ' '.join(f'{b:02x}' for b in value)
+        bpftool(f"map update id {bss_map_id} key hex 00 00 00 00 value hex {value_hex}")
-- 
2.47.3