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
