[ZOOKEEPER-1197] Incorrect socket handling of 4 letter words for NIO

• Type: Bug
• Status: Resolved
• Priority: Critical
• Resolution: Won't Fix
• Affects Version/s: 3.3.3, 3.4.0
• Fix Version/s: 3.5.0
• Component/s: server

Release Note

We'll address the problem in ZOOKEEPER-1346 by moving the 4lws to a separate port.

• Assignee: Camille Fournier
• Reporter: Camille Fournier
• Created: 21/Sep/11 14:37
• Updated: 15/May/14 22:00
• Resolved: 15/May/14 22:00

Description

When transferring a large amount of information from a 4 letter word, especially in interactive mode (telnet or nc) over a slower network link, the connection can be closed before all of the data has reached the client. This is due to the way we handle nc non-interactive mode, by cancelling the selector key.

Instead of cancelling the selector key for 4-letter-words, we should instead flag the NIOServerCnxn to ignore detection of a close condition on that socket (CancelledKeyException, EndOfStreamException). Since the 4lw will close the connection immediately upon completion, this should be safe to do.

See ZOOKEEPER-737 for more details

Issue Links

• relates to: ZOOKEEPER-805 four letter words fail with latest ubuntu nc.openbsd
• relates to: ZOOKEEPER-1346 Add Jetty HTTP server support for four letter words.