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fix(network): replace decnet_lan when driver differs (macvlan<->ipvlan)

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The create helpers short-circuited on name alone, so a prior macvlan
deploy left Docker's decnet_lan network in place. A subsequent ipvlan
deploy would no-op the network create, then container attach would try
to add a macvlan port on enp0s3 that already had an ipvlan slave —
EBUSY, agent 500, docker ps empty.

Now: when the existing network's driver disagrees with the requested
one, disconnect any live containers and DROP it before recreating.
Parent-NIC can host one driver at a time.

Also: setup_host_{macvlan,ipvlan} opportunistically delete the opposite
host-side helper so we don't leave cruft across driver swaps.
This commit is contained in:
anti
2026-04-19 18:12:28 -04:00
parent 6245786289
commit 42b5e4cd06
2 changed files with 89 additions and 35 deletions
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90
decnet/network.py
View File

@@ -126,22 +126,46 @@ def allocate_ips(
# Docker MACVLAN network
# ---------------------------------------------------------------------------
def create_macvlan_network(
def _ensure_network(
client: docker.DockerClient,
*,
driver: str,
interface: str,
subnet: str,
gateway: str,
ip_range: str,
extra_options: dict | None = None,
) -> None:
"""Create the MACVLAN Docker network. No-op if it already exists."""
existing = [n.name for n in client.networks.list()]
if MACVLAN_NETWORK_NAME in existing:
return
"""Create the decnet docker network with ``driver``, replacing any
existing network of the same name that was built with a different driver.
Why the replace-on-driver-mismatch: macvlan and ipvlan slaves can't
coexist on the same parent interface. If an earlier run left behind a
macvlan-driver network and we're now asked for ipvlan (or vice versa),
short-circuiting on name alone leaves Docker attaching new containers
to the old driver and the host NIC ends up EBUSY on the next port
create. So: when driver disagrees, disconnect everything and DROP it.
"""
options = {"parent": interface}
if extra_options:
options.update(extra_options)
for net in client.networks.list(names=[MACVLAN_NETWORK_NAME]):
if net.attrs.get("Driver") == driver:
return # right driver, leave it alone
# Wrong driver — tear it down. Disconnect any live containers first
# so `remove()` doesn't refuse with ErrNetworkInUse.
for cid in (net.attrs.get("Containers") or {}):
try:
net.disconnect(cid, force=True)
except docker.errors.APIError:
pass
net.remove()
client.networks.create(
name=MACVLAN_NETWORK_NAME,
driver="macvlan",
options={"parent": interface},
driver=driver,
options=options,
ipam=docker.types.IPAMConfig(
driver="default",
pool_configs=[
@@ -155,6 +179,21 @@ def create_macvlan_network(
)
def create_macvlan_network(
client: docker.DockerClient,
interface: str,
subnet: str,
gateway: str,
ip_range: str,
) -> None:
"""Create the MACVLAN Docker network, replacing an ipvlan-driver one of
the same name if necessary (parent-NIC can't host both drivers)."""
_ensure_network(
client, driver="macvlan", interface=interface,
subnet=subnet, gateway=gateway, ip_range=ip_range,
)
def create_ipvlan_network(
client: docker.DockerClient,
interface: str,
@@ -162,25 +201,12 @@ def create_ipvlan_network(
gateway: str,
ip_range: str,
) -> None:
"""Create an IPvlan L2 Docker network. No-op if it already exists."""
existing = [n.name for n in client.networks.list()]
if MACVLAN_NETWORK_NAME in existing:
return
client.networks.create(
name=MACVLAN_NETWORK_NAME,
driver="ipvlan",
options={"parent": interface, "ipvlan_mode": "l2"},
ipam=docker.types.IPAMConfig(
driver="default",
pool_configs=[
docker.types.IPAMPool(
subnet=subnet,
gateway=gateway,
iprange=ip_range,
)
],
),
"""Create an IPvlan L2 Docker network, replacing a macvlan-driver one of
the same name if necessary (parent-NIC can't host both drivers)."""
_ensure_network(
client, driver="ipvlan", interface=interface,
subnet=subnet, gateway=gateway, ip_range=ip_range,
extra_options={"ipvlan_mode": "l2"},
)
@@ -204,10 +230,14 @@ def _require_root() -> None:
def setup_host_macvlan(interface: str, host_macvlan_ip: str, decky_ip_range: str) -> None:
"""
Create a macvlan interface on the host so the deployer can reach deckies.
Idempotent — skips steps that are already done.
Idempotent — skips steps that are already done. Drops a stale ipvlan
host-helper first: the two drivers can share a parent NIC on paper but
leaving the opposite helper in place is just cruft after a driver swap.
"""
_require_root()
_run(["ip", "link", "del", HOST_IPVLAN_IFACE], check=False)
# Check if interface already exists
result = _run(["ip", "link", "show", HOST_MACVLAN_IFACE], check=False)
if result.returncode != 0:
@@ -227,10 +257,14 @@ def teardown_host_macvlan(decky_ip_range: str) -> None:
def setup_host_ipvlan(interface: str, host_ipvlan_ip: str, decky_ip_range: str) -> None:
"""
Create an IPvlan interface on the host so the deployer can reach deckies.
Idempotent — skips steps that are already done.
Idempotent — skips steps that are already done. Drops a stale macvlan
host-helper first so a prior macvlan deploy doesn't leave its slave
dangling on the parent NIC after the driver swap.
"""
_require_root()
_run(["ip", "link", "del", HOST_MACVLAN_IFACE], check=False)
result = _run(["ip", "link", "show", HOST_IPVLAN_IFACE], check=False)
if result.returncode != 0:
_run(["ip", "link", "add", HOST_IPVLAN_IFACE, "link", interface, "type", "ipvlan", "mode", "l2"])

34
tests/test_network.py
View File

@@ -76,11 +76,12 @@ class TestIpsToRange:
# ---------------------------------------------------------------------------
class TestCreateMacvlanNetwork:
def _make_client(self, existing=None):
def _make_client(self, existing=None, existing_driver="macvlan"):
client = MagicMock()
nets = [MagicMock(name=n) for n in (existing or [])]
for net, n in zip(nets, (existing or [])):
net.name = n
net.attrs = {"Driver": existing_driver, "Containers": {}}
client.networks.list.return_value = nets
return client
@@ -104,11 +105,12 @@ class TestCreateMacvlanNetwork:
# ---------------------------------------------------------------------------
class TestCreateIpvlanNetwork:
def _make_client(self, existing=None):
def _make_client(self, existing=None, existing_driver="ipvlan"):
client = MagicMock()
nets = [MagicMock(name=n) for n in (existing or [])]
for net, n in zip(nets, (existing or [])):
net.name = n
net.attrs = {"Driver": existing_driver, "Containers": {}}
client.networks.list.return_value = nets
return client
@@ -126,6 +128,18 @@ class TestCreateIpvlanNetwork:
create_ipvlan_network(client, "wlan0", "192.168.1.0/24", "192.168.1.1", "192.168.1.96/27")
client.networks.create.assert_not_called()
def test_replaces_macvlan_network_with_ipvlan(self):
"""If an old macvlan-driver net exists under the same name, remove+recreate.
Short-circuiting on name alone leaves Docker attaching containers to the
wrong driver — on the next port create the parent NIC goes EBUSY because
macvlan and ipvlan slaves can't share it."""
client = self._make_client([MACVLAN_NETWORK_NAME], existing_driver="macvlan")
old_net = client.networks.list.return_value[0]
create_ipvlan_network(client, "wlan0", "192.168.1.0/24", "192.168.1.1", "192.168.1.96/27")
old_net.remove.assert_called_once()
client.networks.create.assert_called_once()
assert client.networks.create.call_args[1]["driver"] == "ipvlan"
def test_uses_same_network_name_as_macvlan(self):
"""Both drivers share the same logical network name so compose files are identical."""
client = self._make_client([])
@@ -154,8 +168,10 @@ class TestSetupHostMacvlan:
mock_run.return_value = MagicMock(returncode=0)
setup_host_macvlan("eth0", "192.168.1.5", "192.168.1.96/27")
calls = [c[0][0] for c in mock_run.call_args_list]
# "ip link add <iface> link ..." should not be called when iface exists
assert not any("link" in cmd and "add" in cmd and HOST_MACVLAN_IFACE in cmd for cmd in calls)
# "ip link add <iface> link ..." should not be called when iface exists.
# (The opportunistic `ip link del decnet_ipvlan0` cleanup is allowed.)
add_cmds = [cmd for cmd in calls if cmd[:3] == ["ip", "link", "add"]]
assert not any(HOST_MACVLAN_IFACE in cmd for cmd in add_cmds)
@patch("decnet.network.os.geteuid", return_value=1)
def test_requires_root(self, _):
@@ -182,9 +198,13 @@ class TestSetupHostIpvlan:
def test_uses_ipvlan_iface_name(self, mock_run, _):
mock_run.side_effect = lambda cmd, **kw: MagicMock(returncode=1) if "show" in cmd else MagicMock(returncode=0)
setup_host_ipvlan("wlan0", "192.168.1.5", "192.168.1.96/27")
calls = [str(c) for c in mock_run.call_args_list]
assert any(HOST_IPVLAN_IFACE in c for c in calls)
assert not any(HOST_MACVLAN_IFACE in c for c in calls)
calls = [c[0][0] for c in mock_run.call_args_list]
# Primary interface created is the ipvlan slave.
assert any("add" in cmd and HOST_IPVLAN_IFACE in cmd for cmd in calls)
# The only macvlan reference allowed is the opportunistic `del`
# that cleans up a stale helper from a prior macvlan deploy.
macvlan_refs = [cmd for cmd in calls if HOST_MACVLAN_IFACE in cmd]
assert all(cmd[:3] == ["ip", "link", "del"] for cmd in macvlan_refs)
@patch("decnet.network.os.geteuid", return_value=1)
def test_requires_root(self, _):