fix: apply idle timeout to domain fronting relay#416
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9seconds merged 4 commits into9seconds:masterfrom Mar 29, 2026
Merged
fix: apply idle timeout to domain fronting relay#4169seconds merged 4 commits into9seconds:masterfrom
9seconds merged 4 commits into9seconds:masterfrom
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Domain fronting relay (for non-Telegram traffic) had no idle timeout, causing worker pool exhaustion under traffic spikes. The ProxyOpts.IdleTimeout field existed but was never wired into the proxy. Now domain fronting connections are wrapped with per-read/write deadlines reset to the configured idle timeout (default 1m), so stale or slowloris-style connections are reaped promptly. Fixes 9seconds#378
When the worker pool rejected a connection (ErrPoolOverload), the accepted net.Conn was never closed — leaking a file descriptor and TCP socket per rejected connection. Under sustained traffic spikes this compounds the problem: leaked descriptors reduce the capacity for new dials (including to the fronting domain), accelerating the failure cascade described in 9seconds#378.
- avoid deprecated DefaultIdleTimeout, use time.Minute directly - simplify embedded field selectors (QF1008)
This was referenced Mar 28, 2026
dolonet
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Wrap both sides of the Telegram relay in connIdleTimeout, same as already done for domain fronting in 9seconds#416. Without this, if a client disappears (network drop, battery dies), the TCP connection stays formally alive and the goroutine in the worker pool blocks on io.CopyBuffer indefinitely. Under mass client disconnects this accumulates zombie goroutines. Fixes 9seconds#417
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Summary
Fixes #378 — two bugs that together cause proxy failure under non-Telegram traffic spikes.
1. Domain fronting relay has no idle timeout
ProxyOpts.IdleTimeoutwas defined but never wired into the proxy. ThedoDomainFrontingrelay used rawio.CopyBufferwith no deadline, so each forwarded connection could block a worker goroutine indefinitely. Under a burst of probes/scanners/slowloris the pool fills up and legitimate Telegram connections get dropped.Fix: wrap both sides of the domain fronting relay in a
connIdleTimeoutadapter that resets read/write deadlines on every I/O operation. The timeout comes fromnetwork.timeout.idleconfig (default 1m).2. Connection leak on worker pool overflow
When the pool rejected a connection (
ErrPoolOverload), the acceptednet.Connwas never closed — leaking a file descriptor and TCP socket per rejected connection. Under sustained spikes this compounds the problem: leaked descriptors reduce capacity for new dials (including to the fronting domain).Fix:
conn.Close()before logging the concurrency limit event, consistent with the blocklist/allowlist paths.Changes
mtglib/conns.go— addconnIdleTimeoutwrappermtglib/proxy.go— storeidleTimeoutin Proxy; wrap domain fronting relay connections; close conn on pool overflowmtglib/proxy_opts.go— addgetIdleTimeout()with default fallbackinternal/cli/run_proxy.go— passconf.Network.Timeout.IdleintoProxyOpts