Description of problem:
The kernel supports TCP_FASTOPEN (the system include files have it, the
/proc/sys/net/ipv4/tcp_fastopen magic file exists) but there is no definition
of MSG_FASTOPEN (required for applications using the feature to build).
Version-Release number of selected component (if applicable):
F24, with glibc-headers-2.23.1 has it present in /usr/include/bits/socket.h
I was attempting to compile a (bleeding-edge development version) of an
application which can use TCP Fast Open (RFC 7413). The specific application,
Exim, is not delivered by Red Hat but is the globally dominant internet-facing MTA
according to one scanning site.
TCP Fast Open is also expected to be of interest for general web access
(it can remove one roundtrip time; important for shortlived connections).
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.