The map[key.NodePublic][]netip.Prefix that flows from route manager
commits to WireGuard device syncs has subtle semantics (a nil value
means the peer was removed or no longer contributes any prefixes)
that were documented on routemanager.Result.AllowedIPs and then
re-documented, or not, at each signature that passed it along. Give
it a named type, PeersWithRouteChanges, and document the nil
semantics once on it.
Updates #12542
Change-Id: I2566361a5331eb11b2b70a5bcdb497cc20ee561d
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Give nodeBackend a RouteManager and keep it in sync as routing
inputs change: full netmaps resync the whole peer set (removals plus
no-op-cheap upserts), incremental netmap deltas mirror their peer
upserts and removes into the same mutation batch, and
authReconfigLocked pushes the routing-relevant prefs (exit node,
subnet route acceptance, OneCGNAT) after resolving the exit node's
stable ID to its current numeric node ID.
A selected exit node that doesn't resolve to a current peer (a
nonexistent node, or MDM's "auto:any" placeholder awaiting
resolution) is not the same as no exit node: per the long-standing
ipn.Prefs.ExitNodeID contract, it blackholes internet traffic rather
than letting it escape to the local network. RouteManager's Prefs
gains an ExitNodeSelected bit so its OS route set keeps the default
routes in that case, with no outbound peer to carry them, matching
what routerConfigLocked does today, as pinned by TestRouterConfigExitNodeBlackhole in the previous commit.
All mutations happen with nodeBackend.mu held, satisfying the
RouteManager's serialized Begin/Commit contract.
Nothing consumes its snapshots yet; the wgengine data plane and OS
router wiring come next.
Updates #12542
Change-Id: I677b6b2c9efb8e41b3d27071bd9db73e01640d3b
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Add a new RouteManager type that tracks per-peer self addresses and
advertised routes and incrementally maintains two read-only
snapshots: an IP-to-outbound-peer bart table carrying the per-peer
attributes the data plane needs (jailed state, masquerade addresses),
and a coarsened OS route set (including OneCGNAT consolidation).
Mutations are staged in a transaction (Begin/Commit) and applied to
the snapshots via bart's Persist methods, which path-copy only the
few trie nodes along the affected prefix, so a single-peer delta
costs a bounded amount of work independent of the number of peers,
instead of the O(n) full-world rebuild done today. Snapshots are
published via atomic pointer swap for lock-free reads on the hot
path, and Commit reports which peers' allowed IPs changed so callers
can sync wireguard-go incrementally. This is the same immutable value
snapshot pattern as used in the recent containerboot change,
364b952d62.
Nothing uses it yet; this is pulled out of a future change that wires
it into ipnlocal and wgengine, to make that PR smaller.
Updates #12542
Change-Id: Iccc5258024e6f90311835b79fd2d83b2adb0d09d
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Brad FitzpatrickandBrad Fitzpatrick