Re: TCP vs urgent data [was Re: poll(): IN/OUT vs {RD,WR}NORM]

>> I might rip out the OOB stuff just to find and fix anything trying
>> to use it, though.
> I think ripping it out would be the right thing.  And I suspect very
> little would notice.

I just did a first pass, doing

find . -type f -print0 | xargs -0 mcgrep -H -l MSG_OOB

in /usr/src.

Most of it is no surprise, or is irrelevant here: telnet and ftp,
documentation, the kernel support that backends it, sys/compat, those
are expected.

But I got one surprise: rlogin{,d}.  And I had a quick look at the
code - it actually _uses_ it.  It is not a case where completely
ignoring URG will work.  (It actually uses it as out-of-band data, too.
You'd almost think it came from the same people who tried to turn the
urgent pointer into out-of-band data in the first place.)

Fortunately or unfortunately, I don't care about rlogin.  I would ditch
it when eliminating MSG_OOB.  In theory, eliminating MSG_OOB is wrong,
because TCP may not be the only protocol that uses it.  My sweep found
sys/netiso/tp_usrreq.c, and searching for SSD_RCVATMARK under sys/
finds hits in netiso as well as netinet.  But I care about netiso about
as much as I care about rlogin; I certainly don't mind losing it for
long enough to find everything using TCP "OOB".

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