Re: RST not emitted on listen backlog full?

[der Mouse <mouse%Rodents-Montreal.ORG@localhost>]

> We've been doing some automated load testing and have noticed
> something curious.  When the TCP SYN cache code can't create a new
> socket for an incoming connection because the listen backlog is full
> (128 max) there is a call to tcp_respond which seems intended to
> cause a RST, but we never see the RST hit the wire.  We see no reason
> why and wonder if others have noticed this (mis-)behavior.

Well, quite aside from whether the code does what it is intended to do,
it seems to me that the actual behaviour is the right behaviour: if we
can't handle it now, but the reason could plausibly have gone away by
the time a retransmit happens (which it seems to me applies here), then
I'd say it's better to drop the packet and hope things are better when
we get the retransmit than to RST it.

/~\ The ASCII                             Mouse
\ / Ribbon Campaign
 X  Against HTML                mouse%rodents-montreal.org@localhost
/ \ Email!           7D C8 61 52 5D E7 2D 39  4E F1 31 3E E8 B3 27 4B