The engine kept its own longest-prefix-match table (peerByIPRoute),
rebuilt from the full peer list on every reconfig, to route outbound
packets and answer PeerKeyForIP. That's now the route manager's job:
LocalBackend already installs a PeerByIPPacketFunc backed by the
RouteManager's incrementally-maintained outbound table, so the
engine's copy was redundant state with redundant O(n peers) rebuild
work.
Delete the table, the PeerKeyForIP interface method, and the BART-only
default callback. LocalBackend's peerForIP now queries the
RouteManager's outbound table directly for the subnet-route and
exit-node fallback. Engines running without a LocalBackend (such as
wgengine/bench) must install their own outbound peer lookup, since the
device's standard AllowedIPs trie only covers peers that already
exist and can't lazily create them.
Updates #12542
Change-Id: I25100399e273ed6c2bb1f6136b7cd81bc83e7313
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Previously, any peer added or removed by an incremental netmap delta
was only visible to wireguard-go after a full authReconfig: wgcfg's
ReconfigDevice re-installed a PeerLookupFunc closing over a freshly
built map of every peer's allowed IPs, doing O(n) work per change.
Instead, install the wireguard-go device hooks once, backed by live
state. Engine.SetPeerConfigFunc installs a single long-lived
PeerLookupFunc that queries LocalBackend's per-node RouteManager on
demand, and Engine.SyncDevicePeer does O(1) per-peer device sync
(remove, or update allowed IPs) as each delta mutation is applied.
Full reconfigs keep an O(n peers) device sync for now, but with no
lookup closure to reinstall and no removed-peer resurrection race; a
later change removes full-config peer syncing entirely.
The RouteManager's PeerAllowedIPs accessor backs the new hooks: its
sorted output makes unchanged state a no-op update, and its peer
filtering mirrors nmcfg.WGCfg, so expired peers and peers predating
both DERP and disco contribute no prefixes and thus cannot be lazily
created in the device, which matters because wireguard-go validates
inbound source IPs against per-peer allowed IPs.
The engine's SetPeerByIPPacketFunc callback is now authoritative when
installed, since LocalBackend's implementation covers subnet routes
and exit-node routes via the RouteManager's outbound table; the
engine's own reconfig-time BART table only serves engines running
without a LocalBackend.
The forced authReconfig on peer add/remove stays for now: the
WireGuard device no longer needs it, but OS routes, the quad-100
resolver's MagicDNS hosts map, and tstun's masquerade/jailed peer
config are still derived from the full peer set. Making those
delta-aware is the next step before gating it.
Updates #12542
Change-Id: I3ba8c7c324bca0ad0269279d03f53b1f17fb63a2
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
tsdial.Dialer.SetNetMap rebuilt an O(n peers) map of MagicDNS names on
every netmap change. As we move toward per-peer incremental deltas,
this becomes quadratic. This removes it and replaces it with
SetResolveMagicDNS, a callback into LocalBackend that looks up
hostnames from nodeBackend's new nodeByName index (populated alongside
nodeByAddr/nodeByKey on both full and delta paths). The index stores
both FQDNs and short names as keys.
This is the same treatment applied to netlog (8f210454d), wglog
(988b0905b), and drive (1d6989408): stop pushing *netmap.NetworkMap
into subsystems and instead have them pull from LocalBackend's live
data via callbacks.
Updates #12542
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Change-Id: I24557ab0c8a27636e08e4779bcfd3ec633db0a78
Brad Fitzpatrick