fix(quic): dial from ephemeral port instead of reusing listener port#487
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When the dialing transport had an active QUIC listener (as every real node does), dial() tried to bind a separate NioDatagramChannel to the listener's own port using only SO_REUSEADDR. On Linux two UDP sockets cannot share a port without SO_REUSEPORT (an Epoll-only option), so the bind threw BindException. The fallback then re-used the same non-@sharable QUIC codec handler instance on a second channel, which also throws, so the outbound connection never completed and timed out — 0 successful outbound dials on listening nodes. Always bind the dial socket to an ephemeral port (the path already exercised by every passing QUIC test). NAT-consistent dialing for hole punching is unaffected: dialAsListener reuses the listener socket directly. Add QuicServerTestJava.dialWhileListeningCompletes regression test that dials while a listener is active — the previously-untested broken branch.
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When the dialing transport had an active QUIC listener, dial() tried to bind a separate NioDatagramChannel to the listener's own port using only SO_REUSEADDR. On Linux two UDP sockets cannot share a port without SO_REUSEPORT (an Epoll-only option), so the bind threw BindException. The fallback then re-used the same non-@sharable QUIC codec handler instance on a second channel, which also throws, so the outbound connection never completed and timed out — 0 successful outbound dials on listening nodes.
Always bind the dial socket to an ephemeral port (the path already exercised by every passing QUIC test). NAT-consistent dialing for hole punching is unaffected: dialAsListener reuses the listener socket directly.
Add QuicServerTestJava.dialWhileListeningCompletes regression test that dials while a listener is active — the previously-untested broken branch.