Ws over h2 pmd fixes#3637
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…e, client extension offer -- with selftest Three fixes for permessage-deflate on ws-over-h2 (RFC 8441) encapsulated streams, plus a ctest-wired selftest: 1) The encapsulated tx path returned the h2 role's write result, which reflects the POST-COMPRESSION frame size -- with pmd active that is routinely smaller than what the caller passed in, so any well-compressed message made callers checking (wr < len) conclude a short write and kill a healthy connection. The lws_write() contract is to report how much of the CALLER's payload was accepted, and the h1 path already returns orig_len for exactly this reason; do the same, still propagating write errors as < 0. 2) When pmd's compressed output exceeds its chunk buffer, the ws role sets ws->tx_draining_ext and expects the next POLLOUT to send the remaining fragments -- the h1 path services this in rops_handle_POLLOUT_ws() priority 5, before letting the user write anything new. An h2-encapsulated child never reaches that path: its only POLLOUT servicing is the child loop in rops_perform_user_POLLOUT_h2(), which went straight to the user callback. Meanwhile lws_send_pipe_choked() reports choked while tx_draining_ext is set, so a user write loop gated on it never writes again either: the drain never advances and the stream wedges permanently. Service the drain from the child loop, ahead of the user callback. It slots in after the generic 'deal with partial at nwsi' branch that 774c64a ("ws-over-h2: deal with choked nwsi") routes carries-ws children through, preserving its ordering: a child on a backed-up network socket still defers there first, the same priority h1 connections get, and the extension drain only runs once the nwsi partial has cleared. 3) lws_h2_client_handshake() only emitted sec-websocket-version and sec-websocket-protocol, so an lws client could never negotiate permessage-deflate (or any extension) over h2 even against a willing server. RFC 8441 Sect 5 carries the ws handshake headers unchanged over extended CONNECT, so build the same offer list as lws_generate_client_ws_handshake() and emit it after the pseudo-headers; the response side already instantiates accepted extensions in the shared lws_client_ws_upgrade() path. api-test-ws-h2-pmd (needs LWS_WITHOUT_EXTENSIONS=OFF): single-process h2 ws server + client, both offering pmd; the server bulk-sends a 64KB deterministic pattern in 4KB messages gated only on lws_send_pipe_choked(), alternating trivially-compressible blocks (deflated frame far smaller than the payload) with incompressible hash noise (deflated output overflows pmd's default 1KB chunk buffer, forcing tx_draining_ext). It fails if the connection is not genuinely ws-over-h2, if the extended CONNECT did not offer pmd, if any lws_write() reports fewer bytes accepted than requested, if the pattern corrupts, or if the transfer stalls. Reverting any one of the three fixes makes it fail in the corresponding distinct way.
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Uh... this was 4 patches which I have taken into _temp... now it's 1 patch... this is replacing the four patches, or it's in addition to the four patches? Or something else entirely? |
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I am sorry — it was just squashed from previous commits. Nothing new |
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Actually this is a follow up fix for the commits you merged |
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So for what I have on _temp branch, trying to add what you have on your branch now - d4e6802 - gives an empty patch. So I think I am up to date. I will push all this to main later today |
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ws-over-h2: permessage-deflate short return + ext tx-drain wedge