[quake3-bugzilla] [Bug 4060] New: string netcode inconsistency

bugzilla-daemon at icculus.org bugzilla-daemon at icculus.org
Thu May 7 11:43:48 EDT 2009


           Summary: string netcode inconsistency
           Product: ioquake3
           Version: SVN HEAD
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: normal
          Priority: P3
         Component: Misc
        AssignedTo: zakk at icculus.org
        ReportedBy: devhc97 at gmail.com
         QAContact: quake3-bugzilla at icculus.org

1. The MSG_Read[Big]String transforms '%' to '.', the MSG_Write[Big]String does
not. The write functions should be fixed.

2. (Let's call the '%' and extended ASCII characters non-net chars.)

Com_HashKey is a common function that hashes a string. The client scrambles all
usercmds with the Com_HashKey() value of the last received/acknowledged
server-to-client reliable command (I think to verify that it DID receive that
command in case it says that it received it), and the server unscrambles them
with it.

The problem is that on the server Com_HashKey() is used BEFORE/WITHOUT non-net
to '.' conversions take place. That is, the server version of the
server-to-client reliable commands are raw, but they are changed when
transmitted to the client (through the MSG functions). The result is that if
the server tries to send a command with non-net chars to a client, the server
and client Com_HashKey() value will differ, and usercmd misinterpretation will
occur (aka, bug 2719).

This behaviour was not noticed because when the clients send chat or other
commands, they will have been MSG-processed by the time the server tries to do
something with them, like broadcast it to everyone. And seemingly the server
game has never sent non-net chars on its own.

Com_HashKey should be ditched and a new NET_HashKey or MSG_HashKey should be
used instead, which differs from the original one only in that it behaves as if
the given strings are MSG-processed, that is, it should use '.' for every
non-net char.

PS: I believe we can cross-compatibly change the net code to use non-net chars
across ioquake3 clients: on ioq3 servers, non-ioquake3 clients will see '.',
but will suffer no other side effects, and ioq3 clients will be able to use
non-ioq3 servers as well. But nontheless, I think the above should be fixed for

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