2 Commits
Author SHA1 Message Date
Zoltan Papp 28657607c1 [client] Keep interface discovery out of the bind open path (#8226)
* [client] Keep interface discovery out of the bind open path

Since 0.81.0 a userspace-mode agent whose interface name is not covered
by the interface blacklist deadlocks while bringing the device up, and
the daemon, the GUI and the service stop all hang. wireguard-go holds
the device net lock across bind.Open, our bind builds the UDP mux there,
the mux enumerated interfaces in its constructor, and the interface
filter probed every unlisted name through wgctrl. For the agent's own
interface that probe connected to the daemon's own UAPI endpoint and
waited, with no deadline, for a reply the handler could only give after
taking the same lock. #7346 moved the first enumeration from the stdnet
constructor, which ran before the device existed, to this call site.

The mux no longer discovers interfaces when it is constructed. It
records whether its socket is bound to an unspecified address and
GetConn uses that instead of the length of the discovered list, while
GetListenAddresses keeps refreshing on demand, which pion calls during
candidate gathering outside the device locks. The WireGuard detector
also answers for the agent's own interface without probing, so no
filter asks the daemon about itself.

* [client] Take the agent's own interface name in the detector constructor

Every device implementation reports the configured name, so there is no
later name to follow and the setter was state without a reader that
needed it. The detector takes the name once and compares without a lock.

* [client] Create the default mux Net in the constructor

With discovery moved to GetListenAddresses, the nil Net fallback ran
there as well, and the first concurrent callers raced on writing it.
stdnet.NewNet does no discovery, so the constructor can create it before
the mux is shared and the address refresh only reads it.

* [client] Follow the created interface name in the detector

Android ignores the configured interface name and keeps the TUN name
returned by CreateUnmonitoredTUNFromFD, so the detector built from the
configuration would still probe the agent's real interface. The engine
updates the detector with wgInterface.Name() once the interface exists.

* [client] Keep the detector's own interface name immutable

On Android the kernel names the TUN and the name can change again on
renew, while the UAPI socket cannot be opened there at all, so neither
the probe nor a name set after creation can identify the agent's own
interface reliably. Excluding that interface on Android belongs to the
interface discovery the app provides. Everywhere else the configured
name is the created name, so the constructor argument is enough and the
detector needs no setter and no lock on the hot path.
2026-10-16 02:16:45 +02:00
Riccardo Manfrin 3e85e40be2 [client] Cache the WireGuard interface check shared by ICE agents (#8001)
* [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.
2026-10-09 11:03:34 +02:00