The controlled side already answers a refused port-forward channel with
opened { success: false, message }; on the multiplexed path TunnelHandle::
on_frame only logged that message at debug and closed the channel, so the
user saw a closed connection with no explanation, worst on the RDP path
where only the RDP client's own error remained. on_frame now returns the
message the window should show, deduplicated per distinct reason (capped
at MAX_REPORTED_OPEN_ERRORS) so one page load's dozen refused connections
surface one dialog per reason instead of a dozen.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EZ49AbZJYfm8NTp5yDPMab
Fix 1 (critical): clamp SendCredit to MAX_SEND_CREDIT (= CHANNEL_WINDOW)
in both new() and add(), so a peer with tunnel permission can no longer
advertise an unbounded window and force the controlled side's unbounded
FrameSink::Direct sink to buffer unlimited target data per channel.
Fix 2: rename the "starve" test to many_channels_echo_concurrently and
drop its (untrue) starvation claim, since it opens every channel before
the bulk transfer starts. Add a_channel_opened_during_a_bulk_transfer_
is_served_promptly, which opens the small channel while the bulk one is
demonstrably mid-flight.
Fix 3: only look up the tunnel permission for `open` frames in the
PortForwardChannel arm of on_message, instead of once per data frame.
Fix 4: two rustfmt deviations in connection.rs (matches! wrapping and a
tuple literal), fixed by hand without a blanket cargo fmt run.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EZ49AbZJYfm8NTp5yDPMab
many_channels_echo_concurrently_and_a_bulk_one_does_not_starve_them dropped
its bulk write half as soon as writing finished, which shuts down the write
side of the socket and, by design (see the design doc's TCP half-close
non-goal; today's run_forward does the same), ends the whole channel. Keep
the write half alive until the reader is done so the test measures
starvation, not half-close. Add a_local_half_close_ends_the_whole_channel to
pin that limitation in code.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EZ49AbZJYfm8NTp5yDPMab
Publishing after spawn let a loop that dies immediately reset the state
first, so the later publish pinned it at Muxed with a dead handle
forever. Also adds a test pinning open-before-data ordering across many
concurrently opened channels, and drops an unused Clone derive.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EZ49AbZJYfm8NTp5yDPMab
Replace cumulative accounting (granted/received) with remaining credit
tracking to prevent u32 overflow after 4 GiB of data on a single channel.
Wire behavior is identical, but the fix allows large file transfers
without mid-stream channel closure.
Add regression test for 8 GiB transfer to verify fix.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EZ49AbZJYfm8NTp5yDPMab
