netdev - [PATCH RFC net-next 0/1] tcp: close socket without reset on incoming data

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Date:   Fri, 18 May 2018 15:01:40 -0400
From:   Debabrata Banerjee <dbanerje@...mai.com>
To:     "David S . Miller" <davem@...emloft.net>, netdev@...r.kernel.org
Cc:     Alexey Kuznetsov <kuznet@....inr.ac.ru>,
        Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>,
        dbanerje@...mai.com
Subject: [PATCH RFC net-next 0/1] tcp: close socket without reset on incoming data

There is a basic problem with TCP sockets, where sending and closing of
data is unreliable. One good example of this is a web server that wants
to send an error back on a HTTP POST and close the socket, however
assuming the POST was of any significant size what really happens is
that the browser gets a broken socket while it is trying to post, and
never reads the error, possible retrying the whole POST a number of
times. This has been well documented by other people, for example this
blog post:

https://blog.netherlabs.nl/articles/2009/01/18/the-ultimate-so_linger-page-or-why-is-my-tcp-not-reliable

Without this patch, our server application has to hang on to a socket
sink all of the POST data, eating up memory and cpu. With this patch
the task is offloaded to the kernel, which uses only a timewait socket
to efficiently ack and discard any incoming data. We've been using a
similar patch internally for years, I think it has applications for
everyone.

Debabrata Banerjee (1):
  tcp: close socket without reset on incoming data

 include/linux/tcp.h      |  4 +++-
 include/uapi/linux/tcp.h |  2 +-
 net/ipv4/tcp.c           | 23 +++++++++++++++++++++--
 net/ipv4/tcp_input.c     | 16 ++++++++++++----
 net/ipv4/tcp_minisocks.c | 15 +++++++++++++++
 5 files changed, 52 insertions(+), 8 deletions(-)

-- 
2.17.0