Matches a real user report after 2 weeks on this version: bandwidth is low,
the client reconnects every 10-20 minutes, sites randomly stop loading or
crawl, and ping visibly jitters. Root cause: the per-target-connection
reader task (handle_relay_message's Connect handler) read from the
upstream target as fast as it would send and forwarded every chunk
straight to send_relay_to_stream -> an immediate UDP datagram, with ZERO
awareness of the client-facing OSTP session's actual congestion window.
The client already gates its own uplink on cwnd (bridge.rs's proxy_ev
select arm); the server's download direction had no equivalent.
On a real (lossy/jittery mobile or Wi-Fi) client path, a fast target (a
CDN, say) gets blasted at the client far beyond what the path can sustain.
That's a self-inflicted loss burst: it wrecks the RTT/RTO estimate (the
"ping jitters" symptom), can push the session into a stall bad enough that
the client's 25s/180s keepalive stall-detection gives up and reconnects
(the "every 10-20 minutes" symptom), and produces exactly the "randomly
stops loading or crawls" experience while it's happening.
Fix: Dispatcher::snapshot_backpressure() computes each session's headroom
(clamped cwnd - in_flight, same clamp(16,16384) the client uses) from the
existing 10ms retransmit tick - no new polling loop. Published to a
lock-free-reader Arc<AtomicI64> per session in a shared map so relay reader
tasks (which don't have access to Dispatcher; it lives on the main loop
task) can check it without touching a lock/mutex on every read. Before
each read, a reader task waits (capped at 2s, so a wedged read can't stall
forever) while headroom is <= 0. New sessions default to a healthy 32
packets until their first snapshot lands (worst case 10ms), so this can't
stall the very first bytes of a fresh connection.
Scoped to the primary TCP CONNECT/proxy path (the one actual web browsing
uses); UDP relay/TURN is unaffected. No load test against real network
jitter was possible in this environment - the mechanism directly targets
the identified cause, but real-world confirmation is still needed.
- Flutter: Hide 'DNS Server' field and force '10.1.0.1' if connection link contains owndns=true
- Flutter: Remove 'Use Provider DNS' toggle to eliminate client-side choice
- Server (relay.rs): Intercept DNS queries targeting '10.1.0.1:53' and process them via internal DnsServer if DNS is enabled
- Server (api.rs): Continue appending owndns=true to subscription links to enforce internal DNS logic on clients
- ostp-server/relay.rs: remove DNS port 53 interception — DNS queries
now pass through to the actual DNS server as regular TCP connections
- ostp-client/native_handler.rs (Windows): add explicit gateway/32 route
via real interface BEFORE setting default route via TUN to prevent loop
- ostp-client/native_handler.rs (Linux): properly detect real gateway and
add default route via TUN with metric 10 after server IP exclusion
- Remove redundant extra DNS host routes from Windows setup script
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