Re: [BACKPORT 4.4.y 18/25] tcp/dccp: drop SYN packets if accept queue is full
Greg KH <[email protected]>
| Newsgroups | org.kernel.vger.dccp,org.kernel.vger.linux-kernel,org.kernel.vger.netdev,org.kernel.vger.stable |
|---|---|
| Message-ID | <[email protected]> |
On Fri, Mar 22, 2019 at 04:44:09PM +0100, Arnd Bergmann wrote: > From: Eric Dumazet <[email protected]> > > Per listen(fd, backlog) rules, there is really no point accepting a SYN, > sending a SYNACK, and dropping the following ACK packet if accept queue > is full, because application is not draining accept queue fast enough. > > This behavior is fooling TCP clients that believe they established a > flow, while there is nothing at server side. They might then send about > 10 MSS (if using IW10) that will be dropped anyway while server is under > stress. > > Signed-off-by: Eric Dumazet <[email protected]> > Acked-by: Neal Cardwell <[email protected]> > Acked-by: Yuchung Cheng <[email protected]> > Signed-off-by: David S. Miller <[email protected]> > (cherry picked from commit 5ea8ea2cb7f1d0db15762c9b0bb9e7330425a071) Also queued up for 4.9.y