If a conn.Close call raced conn.ReadFromUDPAddrPort before it could
"register" itself as an active read, the conn.ReadFromUDPAddrPort would
never return.
This commit replaces all the activeRead and breakActiveReads machinery
with a channel. These constructs were only depended upon by
SetReadDeadline, and SetReadDeadline was unused.
Updates #16707
Signed-off-by: Jordan Whited <jordan@tailscale.com>
So that conn.PeerAwareEndpoint is always evaluated per-packet, rather
than at least once per packet batch.
Updates tailscale/corp#30042
Signed-off-by: Jordan Whited <jordan@tailscale.com>
A trusted peer relay path is always better than an untrusted direct or
peer relay path.
Updates tailscale/corp#30412
Signed-off-by: Jordan Whited <jordan@tailscale.com>
udpRelayEndpointReady used to write into the peerMap, which required
holding Conn.mu, but this changed in f9e7131.
Updates #cleanup
Signed-off-by: Jordan Whited <jordan@tailscale.com>
Since a [*lazyEndpoint] makes wireguard-go responsible for peer ID, but
wireguard-go may not yet be configured for said peer, we need a JIT hook
around initiation message reception to call what is usually called from
an [*endpoint].
Updates tailscale/corp#30042
Signed-off-by: Jordan Whited <jordan@tailscale.com>
We can't relay a packet received over the IPv4 socket back out the same
socket if destined to an IPv6 address, and vice versa.
Updates tailscale/corp#30206
Signed-off-by: Jordan Whited <jordan@tailscale.com>
Just make [relayManager] always handle it, there's no benefit to
checking bestAddr's.
Also, remove passing of disco.Pong to [relayManager] in
endpoint.handlePongConnLocked(), which is redundant with the callsite in
Conn.handleDiscoMessage(). Conn.handleDiscoMessage() already passes to
[relayManager] if the txID us not known to any [*endpoint].
Updates tailscale/corp#27502
Signed-off-by: Jordan Whited <jordan@tailscale.com>
A lazyEndpoint may end up on this TX codepath when wireguard-go is
deemed "under load" and ends up transmitting a cookie reply using the
received conn.Endpoint.
Updates tailscale/corp#20732
Updates tailscale/corp#30042
Signed-off-by: Jordan Whited <jordan@tailscale.com>
Changes to our src/address family can trigger blackholes.
This commit also adds a missing set of trustBestAddrUntil when setting
a UDP relay path as bestAddr.
Updates tailscale/corp#27502
Signed-off-by: Jordan Whited <jordan@tailscale.com>
Otherwise we can end up mirroring packets to them forever. We may
eventually want to relax this to direct paths as well, but start with
UDP relay paths, which have a higher chance of becoming untrusted and
never working again, to be conservative.
Updates tailscale/corp#27502
Signed-off-by: Jordan Whited <jordan@tailscale.com>
This was previously hooked around direct UDP path discovery /
CallMeMaybe transmission, and related conditions. Now it is subject to
relay-specific considerations.
Updates tailscale/corp#27502
Signed-off-by: Jordan Whited <jordan@tailscale.com>
Relay handshakes may now occur multiple times over the lifetime of a
relay server endpoint. Handshake messages now include a handshake
generation, which is client specified, as a means to trigger safe
challenge reset server-side.
Relay servers continue to enforce challenge values as single use. They
will only send a given value once, in reply to the first arriving bind
message for a handshake generation.
VNI has been added to the handshake messages, and we expect the outer
Geneve header value to match the sealed value upon reception.
Remote peer disco pub key is now also included in handshake messages,
and it must match the receiver's expectation for the remote,
participating party.
Updates tailscale/corp#27502
Signed-off-by: Jordan Whited <jordan@tailscale.com>
Premature cancellation was preventing the work from ever being cleaned
up in runLoop().
Updates tailscale/corp#27502
Signed-off-by: Jordan Whited <jordan@tailscale.com>
If we acted as the allocator we are responsible for signaling it to the
remote peer in a CallMeMaybeVia message over DERP.
Updates tailscale/corp#27502
Signed-off-by: Jordan Whited <jordan@tailscale.com>
udprelay.Server is lazily initialized when the first request is received
over peerAPI. These early requests have a high chance of failure until
the first address discovery cycle has completed.
Return an ErrServerNotReady error until the first address discovery
cycle has completed, and plumb retry handling for this error all the
way back to the client in relayManager.
relayManager can now retry after a few seconds instead of waiting for
the next path discovery cycle, which could take another minute or
longer.
Updates tailscale/corp#27502
Signed-off-by: Jordan Whited <jordan@tailscale.com>
This reverts commit 6a93b17c8c.
The reverted commit added more complexity than it was worth at the
current stage. Handling delta CapVer changes requires extensive changes
to relayManager datastructures in order to also support delta updates of
relay servers.
Updates tailscale/corp#27502
Signed-off-by: Jordan Whited <jordan@tailscale.com>
The relay server now fetches IPs from local interfaces and external
perspective IP:port's via netcheck (STUN).
Updates tailscale/corp#27502
Signed-off-by: Jordan Whited <jordan@tailscale.com>
This enables us to mark nodes as relay capable or not. We don't actually
do that yet, as we haven't established a relay CapVer.
Updates tailscale/corp#27502
Signed-off-by: Jordan Whited <jordan@tailscale.com>
It might complete, interrupting it reduces the chances of establishing a
relay path.
Updates tailscale/corp#27502
Signed-off-by: Jordan Whited <jordan@tailscale.com>
This is simply for consistency with relayManagerInputEvent(), which
should be the sole launcher of runLoop().
Updates tailscale/corp#27502
Signed-off-by: Jordan Whited <jordan@tailscale.com>
relayManager can now hand endpoint a relay epAddr for it to consider
as bestAddr.
endpoint and Conn disco ping/pong handling are now VNI-aware.
Updates tailscale/corp#27502
Updates tailscale/corp#29422
Signed-off-by: Jordan Whited <jordan@tailscale.com>
This commit adds a new type to magicsock, epAddr, which largely ends up
replacing netip.AddrPort in packet I/O paths throughout, enabling
Geneve encapsulation over UDP awareness.
The conn.ReceiveFunc for UDP has been revamped to fix and more clearly
distinguish the different classes of packets we expect to receive: naked
STUN binding messages, naked disco, naked WireGuard, Geneve-encapsulated
disco, and Geneve-encapsulated WireGuard.
Prior to this commit, STUN matching logic in the RX path could swallow
a naked WireGuard packet if the keypair index, which is randomly
generated, happened to overlap with a subset of the STUN magic cookie.
Updates tailscale/corp#27502
Updates tailscale/corp#29326
Signed-off-by: Jordan Whited <jordan@tailscale.com>
Our conn.Bind implementation is updated to make Send() offset-aware for
future VXLAN/Geneve encapsulation support.
Updates tailscale/corp#27502
Signed-off-by: Jordan Whited <jordan@tailscale.com>
relayManager is responsible for disco ping/pong probing of relay
endpoints once a handshake is complete.
Future work will enable relayManager to set a relay endpoint as the best
UDP path on an endpoint if appropriate.
Updates tailscale/corp#27502
Signed-off-by: Jordan Whited <jordan@tailscale.com>
This type improves code clarity and reduces the chance of heap alloc as
we pass it as a non-pointer. VNI being a 3-byte value enables us to
track set vs unset via the reserved/unused byte.
Updates tailscale/corp#27502
Signed-off-by: Jordan Whited <jordan@tailscale.com>
CallMeMaybeVia reception and endpoint allocation have been collapsed to
a single event channel. discoInfo caching for active relay handshakes
is now implemented.
Updates tailscale/corp#27502
Signed-off-by: Jordan Whited <jordan@tailscale.com>
The event loop removes the need for growing locking complexities and
synchronization. Now we simply use channels. The event loop only runs
while there is active work to do.
relayManager remains no-op inside magicsock for the time being.
endpoints are never 'relayCapable' and therefore endpoint & Conn will
not feed CallMeMaybeVia or allocation events into it.
A number of relayManager events remain unimplemented, e.g.
CallMeMaybeVia reception and relay handshaking.
Updates tailscale/corp#27502
Signed-off-by: Jordan Whited <jordan@tailscale.com>
ServerEndpoint will be used within magicsock and potentially elsewhere,
which should be possible without needing to import the server
implementation itself.
Updates tailscale/corp#27502
Signed-off-by: Jordan Whited <jordan@tailscale.com>
relayManager will eventually be responsible for handling the allocation
and handshaking of UDP relay server endpoints.
relay servers are endpoint-independent, and Conn must already maintain
handshake state for all endpoints. This justifies a new data structure
to fill these roles.
Updates tailscale/corp#27502
Signed-off-by: Jordan Whited <jordan@tailscale.com>
Conn.handleDiscoMessage() now makes a distinction between relay
handshake disco messages and peer disco messages.
Updates tailscale/corp#27502
Signed-off-by: Jordan Whited <jordan@tailscale.com>
Conn.sendDiscoMessage() now verifies if the destination disco key is
associated with any known peer(s) in a thread-safe manner.
Updates #15844
Signed-off-by: Jordan Whited <jordan@tailscale.com>
The previous strategy assumed clients maintained adequate state to
understand the relationship between endpoint allocation and the server
it was allocated on.
magicsock will not have awareness of the server's disco key
pre-allocation, it only understands peerAPI address at this point. The
second client to allocate on the same server could trigger
re-allocation, breaking a functional relay server endpoint.
If magicsock needs to force reallocation we can add opt-in behaviors
for this later.
Updates tailscale/corp#27502
Signed-off-by: Jordan Whited <jordan@tailscale.com>
tstime.GoDuration JSON serializes with time.Duration.String(), which is
more human-friendly than nanoseconds.
ServerEndpoint is currently experimental, therefore breaking changes
are tolerable.
Updates tailscale/corp#27502
Signed-off-by: Jordan Whited <jordan@tailscale.com>
The relay server is still permanently disabled until node attribute
changes are wired up in a future commit.
Updates tailscale/corp#27502
Signed-off-by: Jordan Whited <jordan@tailscale.com>
This feature is "registered" as an ipnlocal.Extension, and
conditionally linked depending on GOOS and ts_omit_relayserver build
tag.
The feature is not linked on iOS in attempt to limit the impact to
binary size and resulting effect of pushing up against NetworkExtension
limits. Eventually we will want to support the relay server on iOS,
specifically on the Apple TV. Apple TVs are well-fitted to act as
underlay relay servers as they are effectively always-on servers.
This skeleton begins to tie a PeerAPI endpoint to a net/udprelay.Server.
The PeerAPI endpoint is currently no-op as
extension.shouldRunRelayServer() always returns false. Follow-up commits
will implement extension.shouldRunRelayServer().
Updates tailscale/corp#27502
Signed-off-by: Jordan Whited <jordan@tailscale.com>
Query for the const quad-100 reverse DNS name, for which a forward
record will also be served. This test was previously dependent on
search domain behavior, and now it is not.
Updates #15607
Signed-off-by: Jordan Whited <jordan@tailscale.com>
The http.StatusMethodNotAllowed status code was being erroneously
set instead of http.StatusBadRequest in multiple places.
Updates #cleanup
Signed-off-by: Jordan Whited <jordan@tailscale.com>
This flag is currently no-op and hidden. The flag does round trip
through the related pref. Subsequent commits will tie them to
net/udprelay.Server. There is no corresponding "tailscale up" flag,
enabling/disabling of the relay server will only be supported via
"tailscale set".
This is a string flag in order to support disablement via empty string
as a port value of 0 means "enable the server and listen on a random
unused port". Disablement via empty string also follows existing flag
convention, e.g. advertise-routes.
Early internal discussions settled on "tailscale set --relay="<port>",
but the author felt this was too ambiguous around client vs server, and
may cause confusion in the future if we add related flags.
Updates tailscale/corp#27502
Signed-off-by: Jordan Whited <jordan@tailscale.com>
This commit implements an experimental UDP relay server. The UDP relay
server leverages the Disco protocol for a 3-way handshake between
client and server, along with 3 new Disco message types for said
handshake. These new Disco message types are also considered
experimental, and are not yet tied to a capver.
The server expects, and imposes, a Geneve (Generic Network
Virtualization Encapsulation) header immediately following the underlay
UDP header. Geneve protocol field values have been defined for Disco
and WireGuard. The Geneve control bit must be set for the handshake
between client and server, and unset for messages relayed between
clients through the server.
Updates tailscale/corp#27101
Signed-off-by: Jordan Whited <jordan@tailscale.com>
Add an explicit case for exercising preferred DERP hysteresis around
the branch that compares latencies on a percentage basis.
Updates #cleanup
Signed-off-by: Jordan Whited <jordan@tailscale.com>
GetReport() may have side effects when the caller enforces a deadline
that is shorter than ReportTimeout.
Updates #13783
Updates #13394
Signed-off-by: Jordan Whited <jordan@tailscale.com>
Write timeouts can be indicative of stalled TCP streams. Understanding
changes in the rate of such events can be helpful in an ops context.
Updates tailscale/corp#23668
Signed-off-by: Jordan Whited <jordan@tailscale.com>
netcheck.Client.GetReport() applies its own deadlines. This 2s deadline
was causing GetReport() to never fall back to HTTPS/ICMP measurements
as it was shorter than netcheck.stunProbeTimeout, leaving no time
for fallbacks.
Updates #13394
Updates #6187
Signed-off-by: Jordan Whited <jordan@tailscale.com>
Jordan WhitedandGitHub
