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Rob Martin
00f8e91c94
* reverseproxy: close backend body and hijacked socket on upgrade setup failures
When an upstream response indicates an HTTP upgrade (101 Switching Protocols),
handleUpgradeResponse takes ownership of res.Body and subsequently hijacks
the client connection.
However, if any setup check fails prior to starting handleUpgradeTunnel
(such as mismatched upgrade headers, non-writable body assertion failure,
hijack unsupported, or handshake buffer flush errors), the function returned
early without closing res.Body or the hijacked client socket.
Because calling Hijack() permanently disables net/http's automatic connection
cleanup, and raw TCP sockets are not closed by the garbage collector, these
early failure exits leaked file descriptors into CLOSE_WAIT/ESTABLISHED.
Fix this by:
1. Adding a deferred cleanup guard that closes res.Body and any hijacked
front connection unless the tunnel successfully takes ownership.
2. Wrapping connections with onceCloseConn to ensure idempotent closure
while preserving optional CloseWrite (TCP half-close) support.
3. Adding TestUpgradeResponseCleanupOnFailure to verify cleanup.
* reverseproxy: test post-hijack cleanup and remove once-close wrappers
Cover handshake flush and buffered backend-write failures after successful hijacking, checking that both connections close. Keep setup-failure cleanup while using the original connections directly.
Code and tests were AI-assisted using an OpenAI coding assistant in Pi.
(cherry picked from commit 62bc606433)