* [client] Take a WireGuard detector through the interface filter
The interface filter answers whether an interface is a WireGuard device by opening
a wgctrl client and asking for it, and it does that for every interface it is given.
Nothing about that call is tied to the caller, so it can be answered by a shared
object instead of being repeated, but the filter has no way to receive one.
InterfaceFilter and the constructors that build one now take a detector, and the ICE
config carries it so that every agent can be handed the same one. Nobody supplies a
detector yet: a nil one probes on every call, which is what the filter did before, so
this changes no behaviour.
* [client] Share one WireGuard detector across every ICE agent
Creating an ICE agent builds two interface filters, one for the agent and one for
the transport net it sits on, and each is asked about every host interface. For an
interface the disallow list does not settle, answering means opening a wgctrl client,
which builds a kernel and a userspace client and resolves the netlink family, and
then a round trip that usually just reports the device does not exist. An agent is
created per peer connection attempt, so on a large network that runs constantly:
on a routing peer with ~16000 peers it measured 2.40s of a 66.59s CPU profile, 3.6%,
split evenly between opening the client and the round trip.
The engine now owns a detector and passes it to every agent through the ICE config,
so the answer for an interface is reused instead of being asked again for each agent.
It is kept for a second, short enough that a WireGuard interface appearing is picked
up before ICE settles on candidates over it.
The callers that build one filter and keep it, the relay and the UDP mux, keep
passing nil and so keep probing, which costs them nothing at their rate.
* [client] Recheck the WireGuard cache inside the singleflight group
A caller that saw an expired entry could enter the singleflight group
after another caller had already refreshed the entry and left it, and
probe the interface a second time. Read the cache again inside the group
before probing.
This also makes the concurrent probe test independent of scheduling: a
late caller finds the fresh entry instead of starting a new probe.
* [client] Drop expired WireGuard detector entries
The detector lives as long as the engine and kept an entry for every
interface name it was ever asked about. On hosts that churn interfaces,
such as container veths, the map only grew. Remove expired entries when
a new answer is stored; the map holds a few dozen names at most, so the
sweep is cheap and runs at most once per interface per TTL.
* [client] Skip the disallow-list filter test on iOS
InterfaceFilter does not apply the disallow list on iOS, so the subtest
reaches the probe there and its no-probe assertion cannot hold.
* [client] Discover interfaces lazily in stdnet instead of at construction
stdnet.NewNet and NewNetWithDiscover ended with
return n, n.UpdateInterfaces()
handing back a non-nil *Net together with the discovery error. Three of the
five call sites (Engine.newWgIface, ice.NewAgent, SingleSocketUDPMux) logged
the error and kept using the instance, which is only safe as long as the
instance still works after a failed discovery.
That stopped being true when Interfaces() gained a lazily refreshed cache:
updateInterfaces sets lastUpdate only on success, so after a failed
construction the 30s cache guard never holds and Interfaces() returns an
error rather than the empty list it used to return. Feeding such an instance
to pion is worse than passing nothing at all - ice.NewAgent falls back to its
own stdnet when Net is nil, and the interface blacklist is applied separately
through AgentConfig.InterfaceFilter, so the fallback loses nothing. Instead,
a transient discovery failure (the Android bridge at boot, or an interface
disappearing between net.Interfaces() and Interface.Addrs()) turned into a
hard "error getting local interfaces" from ice.NewAgent, and aborted the STUN
and TURN probes, which never even need the interface list.
Since the accessors already refresh a stale cache on demand, the eager
discovery in the constructors is redundant: drop it, make both constructors
infallible, and let the discovery error surface at the call that actually
needs the interfaces. UpdateInterfaces had no callers left and is not part of
transport.Net, so it is removed along with it.
InterfaceByIndex and InterfaceByName read the cached slice directly and never
refreshed it, so they would have kept reporting ErrInterfaceNotFound forever
on an instance whose first discovery failed. They now go through the same
refresh path as Interfaces().
* [client] Warm the stdnet interface cache at construction
Moving discovery to first use regressed the privileged suites on the three
platforms that always build an ICE bind: Darwin, FreeBSD and Windows time out
in TestWGIface_UpdateAddr, TestRecreation, TestEngine_SSH and
TestEngine_MultiplePeers, while Linux stays green because a host with the
WireGuard kernel module takes the kernel-device branch and never drives the
mux that asks for interfaces.
interfaceFilter probes with wgctrl every interface the disallow list does not
already exclude. Discovering at construction ran that probe before the caller
had an overlay interface of its own; discovering at first use runs it after,
so on a userspace WireGuard platform the probe reaches the UAPI socket of the
same process. The tests reach it because they construct with a nil disallow
list, where the client passes DefaultInterfaceBlacklist and its own interface
is excluded by prefix.
Restore the original timing with an explicit warm-up. The constructors stay
infallible and the error is still reported by the accessor that needs the
interfaces, so the contract this branch is about is unchanged.
* Revert "[client] Warm the stdnet interface cache at construction"
This reverts commit 947e25288f.
* [client] Give the privileged tests the interface blacklist the client uses
The suites that create a WireGuard interface construct stdnet with a nil
disallow list, which the client never does: Engine passes
profilemanager.DefaultInterfaceBlacklist, whose "wt" and "utun" prefixes
exclude the overlay interface before the filter reaches its wgctrl probe.
With an empty list every interface reaches that probe, the one the test has
just created included, and on a userspace WireGuard platform the probe talks
to the UAPI socket of the same process. That is why Darwin, FreeBSD and
Windows timed out here while Linux, which takes the kernel-device branch on a
host with the module loaded, stayed green.
Pass the blacklist in both suites so they exercise the configuration the
client ships. client/iface declares the prefixes locally because
profilemanager imports it.
Also cover the constructors directly: the existing tests build the struct
literal, so nothing asserted that NewNet and NewNetWithDiscover leave the
cache cold.
* [client] Pass the blacklist in the remaining tests that build an interface
Same reason as the previous commit, four call sites it missed: engine_test,
the route manager and systemops suites, and the privileged DNS server suite
all construct stdnet with a nil disallow list and then create a WireGuard
interface. TestAddVPNRoute surfaced it on FreeBSD once the earlier two files
stopped timing out first.
client/internal/dns declares the prefixes locally; profilemanager imports
that package, so it cannot import profilemanager back.
Riccardo Manfrin