ddidderr
ce51d92df0
Follow-up hardening for348a02c, where `listen_addr` was added to Hello and HelloAck as `Option<SocketAddr>`. Code review surfaced three concrete problems that the previous commit left open: 1. Cold-start asymmetry. Discovery and the QUIC/mDNS advertiser are spawned concurrently. If discovery saw a cached peer advertisement before our own advertiser had written `ctx.local_peer_addr`, our outbound Hello carried `listen_addr: None`. The receiver's `peer_record_addr` then returned `None` and silently dropped the Hello while we still recorded their HelloAck, so peer A learned about peer B but B never learned about A until a later handshake happened to win the race. 2. Duplicate game-list pipeline. The previous commit added `refresh_peer_games`, which post-handshake issued a `ListGames` to fetch `peer.games`. The library-sync path (`LibrarySnapshot`) already populates the same field. Both could race on first contact and overwrite each other. Worse, `refresh_peer_games` was misnamed: a `peer_game_count > 0` guard turned it into a fetch-once-then-no-op helper, while `handle_library_summary` independently re-triggered a full handshake when `previous_count == 0` was observed, producing a redundant ping-pong on every first contact. 3. Argument explosion. `perform_handshake_with_peer`, `spawn_library_resync`, and `after_peer_library_recorded` had grown to 6-8 individual parameters and acquired `#[allow(clippy::too_many_arguments)]` opt-outs. Every caller was destructuring the same fields out of `Ctx`/`PeerCtx`. Changes (all in one commit because they jointly enforce the same invariant: "a peer is only ever recorded by its listener address, and the local listener address must exist before we participate in the protocol"): - `Hello.listen_addr` and `HelloAck.listen_addr` are now `SocketAddr`, not `Option<SocketAddr>`. Wire-incompatible, but PROTOCOL_VERSION already moved to 3 in348a02cso no additional version bump is needed. - `required_listen_addr` reads `ctx.local_peer_addr` and returns an `eyre::Result`; `build_hello_from_state` and `build_hello_ack` both call it, so an outbound or inbound Hello can no longer be constructed before the local QUIC listener is bound. The inbound path maps this into a `Response::InternalPeerError` so the remote peer fails cleanly instead of seeing a malformed HelloAck. - `run_peer_discovery` blocks on `wait_for_local_peer_addr` (25 ms poll, shutdown-aware) before subscribing to the mDNS browser. This closes the cold-start race for outbound handshakes at the source. - `refresh_peer_games`, `request_game_list_from_peer`, and the `previous_count == 0` re-handshake trigger are removed. The post-handshake flow now relies solely on `LibrarySummary`/`LibrarySnapshot`/`LibraryDelta` for peer-library state; `ListGames` survives only for the `request_game_details_*` paths that fetch per-game file descriptions on demand. - New `HandshakeCtx` (with `from_ctx` and `from_peer_ctx` constructors) replaces the long argument lists. All `too_many_arguments` allow-attrs in `handshake.rs` are gone, and call sites in `handlers.rs`, `discovery.rs`, and `stream.rs` collapse to a single clone. - `handle_library_delta` no longer acquires a read lock on the apply path: the `peer_addr` lookup moved into the `else` resync branch where it is actually needed. - `accept_inbound_hello`'s `remote_addr` parameter is renamed to `transport_addr`. It is now used only for warn-log formatting, and the new name signals that this is the ephemeral QUIC source port, never the authoritative listener address that gets recorded. User-visible effect: on cold start, peers can no longer end up with an asymmetric view of each other ("A sees B but B never sees A"). First-contact library sync now does one handshake plus one snapshot/delta exchange instead of the previous handshake + ListGames + redundant follow-up handshake. The direct-connect CLI path (`handle_connect_peer_command`) now fails fast with "local peer listener address is not ready" if invoked before the QUIC server has bound; this is intentional - the previous behaviour would have sent a Hello that the receiver had to silently discard. Test Plan: - just fmt - just clippy - just test (80 peer + 3 cli + 5 tauri tests pass) - just build - Manual: bring up `just peer-cli-alpha`/`bravo`/`charlie`, confirm symmetric peer discovery and that games show up on every side after one library digest cycle, with no duplicated ListGames traffic in trace logs. Refs: Review feedback on commit348a02c(listener-address handshake fix). Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
lanspread
Description
Peer-to-peer game library sharing for LAN parties.
- Peers let users browse and download games from each other
- they discover each other on the local network via mDNS
- they exchange library metadata over QUIC
Ships as a Tauri desktop app.
Development
Prerequisites
# install Tauri CLI
cargo install tauri-cli
# install Deno with a package manager or from https://deno.land/
Build or Run
# build
just build
# run
just run
# test
just test
Scripted peer harness
crates/lanspread-peer-cli runs the peer runtime without the GUI and speaks
JSONL on stdin/stdout. It is intended for automated multi-peer smoke tests.
just peer-cli-build
just peer-cli-image
just peer-cli-run alpha